Thermal conductivity of water in general with rise in temperature

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Thermal conductivity of water in general with rise in temperature

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending on temperature

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Depending on the radiating properties, a body will be black when

A. P = 0, x = 0 and a = 1

B. P= 1, T = 0 and a = 0

C. P = 0, x = 1 and a = 0

D. X = 0, a + p = 0 Where a = absorptivity, p = reflectivity, X = transmissivity.

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According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)

A. Pb = pa - pv

B. Pb = pa + pv

C. Pb = pa × pv

D. Pb = pa/pv

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The natural convection air cooled condensers are used in

A. Domestic refrigerators

B. Water coolers

C. Room air conditioners

D. All of these

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In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

A. Parallel flow

B. Counter flow

C. Cross flow

D. All of these

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Which of the following has maximum value of thermal conductivity?

A. Aluminium

B. Steel

C. Brass

D. Copper

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Temperature of steam at around 540°C can be measured by

A. Thermometer

B. Thermistor

C. Thermocouple

D. None of these

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The expression Q = ρ AT⁴ is called

A. Fourier equation

B. Stefan-Boltzmann equation

C. Newton Reichmann equation

D. Joseph-Stefan equation

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The emissive power of a body depends upon its

A. Temperature

B. Wave length

C. Physical nature

D. All of the above

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Thermal conductivity of glass wool varies from sample to sample because of variation in

A. Composition

B. Density

C. Porosity

D. All of the above

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The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

A. Stanton number

B. Biot number

C. Peclet number

D. Grashoff number

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Which of the following is a case of steady state heat transfer?

A. I.C. engine

B. Air preheaters

C. Heating of building in winter

D. None of the above

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Upto the critical radius of insulation,

A. Added insulation will increase heat loss

B. Added insulation will decrease heat loss

C. Convective heat loss will be less than conductive heat loss

D. Heat flux will decrease

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Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without affecting the intervening medium.

A. Cold body to hot body

B. Hot body to cold body

C. Smaller body to larger body

D. Larger body to smaller body

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Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of

A. 0.002

B. 0.02

C. 0.01

D. 0.1

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The radiation emitted by a black body is known as

A. Black radiation

B. Full radiation

C. Total radiation

D. All of these

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According to Prevost theory of heat exchange

A. It is impossible to transfer heat from low temperature source to t high temperature source

B. Heat transfer by radiation requires no medium

C. All bodies above absolute zero emit radiation

D. Heat transfer in most of the cases takes place by combination of conduction, convection and radiation

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A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

A. k₁ k₂

B. (k₁ + k₂)

C. (k₁ + k₂)/ k₁ k₂

D. 2 k₁ k₂/ (k₁ + k₂)

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The ratio of surface convection resistance to the internal conduction resistance is known as

A. Grashoff number

B. Biot number

C. Stanton number

D. Prandtl number

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Moisture would find its way into insulation by vapour pressure unless it is prevented by

A. High thickness of insulation

B. High vapour pressure

C. Less thermal conductivity insulator

D. A vapour seal

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Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)

A. k. A. (dT/dx)

B. k. A. (dx/dT)

C. k. (dT/dx)

D. k. (dx/dT)

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Pick up the wrong case. Heat flowing from one side to other depends directly on

A. Face area

B. Time

C. Thickness

D. Temperature difference

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An ordinary passenger aircraft requires a cooling system of capacity.

A. 2 TR

B. 4 TR

C. 8 TR

D. 10 TR

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A non-dimensional number generally associated with natural convection heat transfer is

A. Grashoff number

B. Nusselt number

C. Weber number

D. Prandtl number

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All radiations in a black body are

A. Reflected

B. Refracted

C. Transmitted

D. Absorbed

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The amount of radiation mainly depends on

A. Nature of body

B. Temperature of body

C. Type of surface of body

D. All of the above

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The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)

A. t_m = (Δt₁ - Δt₂)/ log_e (Δt₁/Δt₂)

B. t_m = log_e (Δt₁/Δt₂)/ (Δt₁ - Δt₂)

C. t_m = t_m = (Δt₁ - Δt₂) log_e (Δt₁/Δt₂)

D. t_m = log_e (Δt₁ - Δt₂)/ Δt₁/Δt₂

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Unit of thermal conductivity in S.I. units is

A. J/m² sec

B. J/m °K sec

C. W/m °K

D. Option (B) and (C) above

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Thermal conductivity of solid metals with rise in temperature normally

A. Increases

B. Decreases

C. Remain constant

D. May increase or decrease depending on temperature

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According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a

A. Grey body

B. Brilliant white polished body

C. Red hot body

D. Black body

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Heat is closely related with

A. Liquids

B. Energy

C. Temperature

D. Entropy

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Accepted Answer

D. May increase or decrease depending on temperature

Thermal conductivity of water in general with rise in temperature

Correct Answer :

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Related Questions

Depending on the radiating properties, a body will be black when

According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)

The natural convection air cooled condensers are used in

In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

Which of the following has maximum value of thermal conductivity?

Temperature of steam at around 540°C can be measured by

The expression Q = ρ AT⁴ is called

The emissive power of a body depends upon its

Thermal conductivity of glass wool varies from sample to sample because of variation in

The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

Which of the following is a case of steady state heat transfer?

Upto the critical radius of insulation,

Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without affecting the intervening medium.

Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of

The radiation emitted by a black body is known as

According to Prevost theory of heat exchange

A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

The ratio of surface convection resistance to the internal conduction resistance is known as

Moisture would find its way into insulation by vapour pressure unless it is prevented by

Pick up the wrong case. Heat flowing from one side to other depends directly on

An ordinary passenger aircraft requires a cooling system of capacity.

A non-dimensional number generally associated with natural convection heat transfer is

All radiations in a black body are

The amount of radiation mainly depends on

The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)

Unit of thermal conductivity in S.I. units is

Thermal conductivity of solid metals with rise in temperature normally

According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a

Heat is closely related with

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Thermal conductivity of water in general with rise in temperature

Correct Answer :

Show all Heat & Mass Transfer MCQ

Related Questions

Depending on the radiating properties, a body will be black when

According to Dalton's law of partial pressures, (where pb = Barometric pressure, pa = Partial pressure of dry air, and pv = Partial pressure of water vapour)

The natural convection air cooled condensers are used in

In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in

Which of the following has maximum value of thermal conductivity?

Temperature of steam at around 540°C can be measured by

The expression Q = ρ AT4 is called

The emissive power of a body depends upon its

Thermal conductivity of glass wool varies from sample to sample because of variation in

The ratio of Nusselt number and the product of Reynold's number and Prandtl number is equal to

Which of the following is a case of steady state heat transfer?

Upto the critical radius of insulation,

Radiation is the process of heat transfer in which heat flows from a ________, in a straight line, without affecting the intervening medium.

Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of

The radiation emitted by a black body is known as

According to Prevost theory of heat exchange

A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be

The ratio of surface convection resistance to the internal conduction resistance is known as

Moisture would find its way into insulation by vapour pressure unless it is prevented by

Pick up the wrong case. Heat flowing from one side to other depends directly on

An ordinary passenger aircraft requires a cooling system of capacity.

A non-dimensional number generally associated with natural convection heat transfer is

All radiations in a black body are

The amount of radiation mainly depends on

The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit)

Unit of thermal conductivity in S.I. units is

Thermal conductivity of solid metals with rise in temperature normally

According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a

Heat is closely related with

Also checkout

The expression Q = ρ AT⁴ is called

The logarithmic mean temperature difference (t_m) is given by (where Δt₁ and Δt₂ are temperature differences between the hot and cold fluids at entrance and exit)